Here the location for 3 parts require for true ending .
- Start in base , the white door for each area had unlocked.
- After 3 parts collected in Castle's Peak , to return base select menu to exit game and load the savefile back.
- Talk to Chiru and give her 3 parts , now go Castle's Peak again to defeat boss .
- In 3 option choose second . ( Chiru will come bring dimension device )
- When defeat Adult Kurona 1st form , in 3 option choose second
- Defeat her and congrats to players for the ending .

Here is the link
https://youtu.be/1tGnUHyqbA8

Updated 26 Feb 2023
The game manual had Compass function that i did read but already forgot at the first place.
( Then 😑 Expressionless Face for it after found I never use it )
- On keyboard press M , for gamepad move right analog stick ( or remap button on calibration )
- When use near by area some will show but not on hidden wall / secret room.
- Include device parts, girls and upgrade items except panties
- Use it to save some time .

Here the video for quick walkthrough

https://youtu.be/XjkC3MSerVc

Here a quick guide for girls and panties place in the video.

https://youtu.be/gqFvlrtT1L4